Motor-driven machine



March 16, 1954 L. J. FAITH-ELL ET AL MOTOR-DRIVEN MACHINE Original FiledJune 16, 1945 Patented Mar. 16, .y 1954 Hansson,

Stockholm,. Sweden,f. assignorsf` to Aktiebolaget Elektrolux, Stockholm,Sweden, a. corporation of vSweden Original application June` 16,19415,'V Serial No.

599,934. Dividedand thisxapplication .December 17, 1949,.v SerialLNo.133,552

Claims priority, applicationiSweden. August 3, 1944 6 Claims.v l

Thepresent' invention relates vto motor' driven machinery, and moreparticularly tomachinery hav-ingan electric motor driveand-automaticprovisions for quickly interrupting the electric current upon overloadof the-machinery. This application is a division of our applicationSerial No. 599,934led June 16, 194.5J which has :become abandoned.

In electrically drivenmachines which are vsubject to temporaryheavyoverloads, it has' previously been known to protect themotor againstdamage from overloadby employing a centrifugalswitch which interruptsthe electric current upon decrease ink the speed of rotationl of themotorshaft. However, whenv the motor shaft andthe driven shaft areconnected by means of a slipping transmission, the speed of the drivenshaft may decrease without any corresponding decrease in the speedof themotorshaft; thereby not affecting the switch. Consequently, thetransmission means may be subjected to considerable wear vdue toslipping.

In othercases, when usingfa belt drive, a certainV degree ofslipping'causes the belt to leave the pulley. This operating conditionis favorable because the durationof the slipping and wear of the'belt isreduced, but,.on the'other hand, itis combined with the disadvantagethat the belt must ibe put back into its place each time. Especiallywith motor driven apparatus and machinery for, common use; such as floorpolishers' and kitchen appliances, thisk disadvantage causes muchtroubleto the operator.

It is, therefore, an object of this invention to provide an`improvement. for: protecting motor driven machinery against damagefromoverload which overcomes and obviates the foregoing disadvantages.

Further objects and advantages of the vinvention .will be apparent fromthe following description considered in` connection with theaccompanying drawings forming part of this specification,.and of which:

Fig. l is a sectional view, taken on the line I-I of Fig..2, ofthe lowerportion of a mixing machine for kitchen use illustrating an embodimentof the invention;

Fig: 2 is ya plan view of the machine, partly in sectionon line II-II ofFig. 1; and

Figs.' 3to 5 are elevation and sectional views, respectively, showingdetails of the machine in Figs. 1 and 2 onv an enlargedscale.

Referringto` Figs'. 1 and reference `character I designates .generallythe housing and' II the base platef of" the mixing machine, the elec- 2tric motor andigearing ofk whicharedesignated by I2 andIS, respectively.Two tools ofthe-machine, agcontainer and an agitator, aredesignatedby`l4 and I5. Further, IIi-designat'esfthe driving belt of themachine, I'I-the motori'pulley and I8=the pulley ofthe gearing.

In the embodiment'of 'the inventionillustrated in Figs. 1 to 5, acentrifugal relay which is adapted to interrupt the electric currentofthe motor I2 upon overload of themachine; applied to the pulley I8.This'relay comprises vtwo governor weights symmetrically pivoted Withinthe pulley on pins I9. Whenn the pulley rotates with an incerasing speedthe'weights 20,` due to increase 'in centrifugal force,v turn orpivotabout the pins I9' to a position corresponding to the speed. Due tothis movement ofthe weights, a sleeve 22, which is slidably mounted onthe hub of the pulley, ispressed inwardly into the pulley and compressesa spring 23 which'tendsftopress the sleeve inwardly (upward in-Fig. 5).

When the speed and hence the centrifugal forcedecreases, the sleevek 22moves outwardly and engages a lever 25, which in turn coacts with thecontrol mechanism of a switch 24; The lever 25 is pivoted on a pin26carried by a support 21 in the gear housing. This supportalso carriesthe switch-and the control means therefor. The switch 24' is a toggleswitch, the .lever 28'of which isy arranged to be actuated'by an anglelever 30 carried by a pin 29-on the supportZ'II One-end of the anglelever 30 is provided with a handle which projects` through thev housingI 0. The lower portion of the angle lever Iliorms-a fork 3l' whichguides theleveri 2lir of the switch.

Another lever 32 is also carried by thepin-29 and coacts with the anglelever 30. The lever32 is'actuatedby a torsion spring 331a1so `mounted onthe-pin 29,` such spring tending to turn the lever 32 i'n a clockwisedirection to the position illustrated in Fig.'- 1. By'means of a smallhook 3'4 onthe lever 32, the langle level- 30 `can-.be actuated to movethe lever 2'8l of theswitch to its oiposition (openposition) when'thelever- 32 is moved in thef clockwise direction just men.- tioned.Thelever 32 is arrangedl to coact with the lever 25.` A- torsionspring35ltends to press the vlever 25 against-atongue-Bof theangle-lever30, sucl'rtongue serving to guide the-lever 25vin relation to the lever32. I

TheA embodiment just described is` operated in 'thez` following` manner.To start theK machine, the 1 handley of" the angle lever 30 isv4 pusheddown sothat thisY leverwill turn about the pin 29"in a counterclockwisekdirection, as seen" in" Fig; 1',

whereby the fork 3| moves the lever 28 of the switch 24 to its onposition (closed position). Simultaneously the hook 34 is engaged andthe lever 32 will `also be moved in a counterclockwise direction, asseen in Fig. 1, until that lever moves to the position shown in Fig. 3.The handle of angle lever 30 is maintained in its down position for afew seconds until the motor speed picks up and the motor shaft rotatesat a normal rate.

Due to rotation of the pulley I8, the outward movement of the Weightsforces the sleeve 22 inwardly into the pulley hub. The lever 25 is thenactuated by the spring 35 to catch and take hold of the lever 32 by atongue 38, thereby keeping the switch in its on position (Fig. 3). Ifthe machine becomes overloaded and the speed of the driven shaftdecreases, the sleeve 22 is pushed outwardly (downward in Figs. 2 and 5)by the spring 23. The lever 25 is thus acted upon and caused to pivot alittle about the pin 26, whereby the tongue 38 becomes disengaged fromthe lever 32. When this occurs the lever 32 is then actuated by thespring 33, and, by means of the hook 34, moves the angle lever and alsothe lever 28 of the switch 24 back to its oil position (Fig. 1). Whenthe machine is stopped manually by pushing up the handle of the lever30, the latter turns about the pin 29 independently of :the lever 32.When the speed of the driven shaft decreases to a certain suitablevalue, however, the lever 32 is released in the manner just describedwhen overload occurs.

The regulator is so adjusted that the electric current will beinterrupted before the belt slips off the pulley. In the event the beltshould slip off, this indicates that the belt should be exchangedbecause it cannot transmit power efficiently due to wear.

While a single embodiment of the invention has been shown and described,it will be apparent i that modifications yand changes may be madeWithout departing from the spirit and scope of the invention, as pointedout in the following claims.

What is claimed is:

1.` Control mechanism comprising a manually operable part movablebetween operative and inoperative positions, a catch mov-able toward andfrom a holding position, a member movable between active and inactivepositions, spring means to bias the member to its inactive position, themember being moved to its active position against the tension of thespring means responsive to manual movement of the part 'from itsinoperative to its operative position, the catch in the holding positionbeing capable of holding and retaining the member in its active positionwhen moved thereto responsive to manual movement of the part, the springmeans being operable to move the member from the active to the inactiveposition when the catch moves from its holding position, the part,responsive to movement of the member from the active to the inactiveposition, being moved from its operative to its inoperative positionwhenever the part at such time is in its operative position, the partalso being manually movable from its operative to its inoperativeposition independently of the member even when the latter is retained inits active position by the catch.

2. Control mechanism for controlling the operation of apparatuscomprising a manually operable part movable between operative andinoperative positions, a catch movable between holding and releasingpositions, flrst spring means to bias the catch to one of its positions,the catch being adapted to be moved to its other position, against thetension of the first spring means, responsive to a condition affected byoperation of the apparatus, a member movable between active and inactivepositions, second spring means to bias the member to its inactiveposition, the member being moved to its active position against thetension of the second spring means responsive to manual movement of thepart from its inoperative to its operative position, the catch in theholding position being capable of holding and retaining the member inits active position when moved thereto responsive to manual movement ofthe part, the second spring means being opera'ble to move the memberfrom the active to the inactive position when the catch moves from itsholding to its releasing position, the part, responsive to movement ofthe member from the active to the inactive position, being moved fromits operative to its inoperative position whenever the part at such timeis in its operative position, the part also being manually movable fromits operative to its inoperative position independently of the membereven when the latter is retained in its active position by the catch andthe catch subsequently moves from its holding to its releasing positionresponsive to the condition affected by operation of the apparatus.

3. Control mechanism for controlling the operation of apparatus having adriven element, such mechanism comprising a manually operable partmovable between on yand off positions, a member movable between activeand inactive L, positions, spring means to bias said member to itsinactive position, a movable catch adapted to move toward and from aholding position responsive to predetermined increase and decrease inspeed, respectively, of the driven element, the member having a regionin the path of movement of the part which is effective to move themember to its active position when the part is moved to its on position,the catch being operable to hold and retain the member in the activeposition when in its catch holding position, the spring means beingoperable to move the member from the active to the inactive positionwhen the catch moves from its holding position, the part being contactedby the region of the member when the latter moves from the active to theinactive position to cause the part to move from the on to the offposition whenever the part at such time is in its on position, the partalso being manually movable from the on'to the off positionindependently of the member even when the latter is held and retained inits active position by the catch.

4. Control mechanism comprising a manually operable part movable betweenoperative and inoperative positions, a pivotally mounted catchangular-ly movable toward and from a holding position, a member movablebetween active and inactive positions, said part and member beingangularly movable with respect to one another about the same axis,torsional spring means at the vicinity of such axis to bias the memberto its inactive position, the member being moved to its active positionagainst the tension of the spring means when the part is manually movedfrom its inoperative to its operative position, the catch in the holdingposition being capable of retaining the member in its active position,the spring means being operable to move the member from the active tothe inactive position thereof when the catch moves from its holdingposition, the

part. upon movement of the member from the active to the inactiveposition, being actuated to move from its yoperative to its inoperativeposition whenever the part at such time is in its op erative position,the part also being manualiy movable from its operative to itsinoperative position independently of the member even when the latter isretained in its active position by the catch.

5. Control mechanism as set forth in claim 2 in which the catch isangularly movable about a first axis between its holding and releasingpositions and. the part and the member are angularly movable withrespect to one another about a second axis perpendicular to said firstaxis, the first spring means to bias the catch to said one positioncomprising a first torsion spring at the vicinity of said rst axis andthe second spring means to bias the member to its inactive positioncomprising a second torsion spring at the vicinity of said second axis.

LARS JOHAN FAITH-ELL. ERIK OSKAR HELGE HANSSON.

References Cited in the le of this patent UNITED STATES PATENTS NumberName Date 934,211 Pomeroy Sept. 14, 1909 1,044,609 Watson Nov. 19, 19121,047,557 Owens Dec. 17, 1912 1,263,978 Lebovici Apr. 16, 1918 1,346,067'louchy July 6, 1920 1,559,595 Dauplaise Oct. 27, 1925 2,100,710 DendelNov. 30, 1937 2,472,526 Frazee June '7, 1949

